Electrolytic cell



Jan, 20 1931. A. GEoRGIEv ELEGTROLYTIC CELL ashun-sneer 1 Filed Oct. 18,1930 xNvENToR Alexaadered La ATToRNEYa IIHNHIINIHI Y Humm Jan. 20, 1931.

A. GEORGIEV ELEcTRoLYTIc CELL Filed Oct. 18. 19:50

2 Sheets-Sheet 2 Rwi. O E m@ m wm -M @YM/.M .AB/ n e Pltented Jul. 20,1931 UNITED STATES yPATENTN oFr-l'cs ALEXANDER GEORGIEV, OF BROOKLYN,NEW Y'OBK, ASSIGNOB T0 AEROVOX WIRELESS CORPORATION, A CORPORATION 0FNEW YORK ELECTBOLYTIC CELL Application led October 18, 1980. SerialkNo.489,521.

My present invention relates to electrolytic cells, useful as rectifiersand lightning arresters, but is more especially applicable to condensersof the electrolytic type, in which the di-electric is formed in a thinfilm upon the surface of the anode by electro-chemical action.

It is an object of the invention to provide an essentially dry condenserof the above type, of stablevand dependable character7 affording highcapacitance in small bulk, of low electrical leakage, self-healing imcharacter and which may be used without likelihood of breakdown infilter circuits and power supply units of radio receiving sets, intelephony and in other relations. Y

Another object is to provide a simple and practical method for producingand forming condensers of the above type, which shall require noexpensive or highly specialized equipment, or close attention ordelicate ad- Justrnent or regulation by highly skilled supervisors.

Another object is to avoid the loss in capacitance and the consequentincrease in cost and bulk, incurred when the expedient ofseries-connection of two or more condensers is resorted to, in order toprevent breakdown under high voltages, the condenser by its mode ofconstruction being rendered operative under higher voltages thanordinary electrolytic condensers.

Another object is to provide a condenser of the above type, devoid ofliquid apt to slosh around in the casing and yet not subject toexcessive heating or excessive evolution of gas pressure during use.

Another object is to provide a condenser of the above type, light inweight and compact in construction, which can be employed withsubstantially equal effectiveness, upright, inverted, horizontal or atany inclination, accord/ing to the space left available by associatedapparatus.

v Another object is to provide an electrolytic condenser of the abovetype, of a minimum number of elements, or parts, yet with adequateshielding between the individual con# denser sections, enclosed in thesame can and superior in performance though devoid of any filling ofpitch, paraliin or the like.

Another object is to provide a condenser of the above type, devoid ofjoints, connections or other surfaces, subject to corrosion by gal-lvanic action or otherwise, which will maintainjts full eflicacy aftereven long period of use or of idleness or disuse, without high leakagecurrents when operation is resumed.

A feature ofthe invention is the lateral misalignment, as by stag erinof the longitudinal edges of the anode and cathode folls of thecondenser roll. By virtue of this staggering, the edge of the cathode isspaced at a substantial distance from that of the anode, and theconcentration of electrostatic field at the anode edge is consequentlyreduced; the undesirable consequences of imperfect film formation at theanode edge (such'as excessive electrical leakage and sparking over)being, to a great extent,- overcome. -By this4 arrangement, while thecapacitance of the condenser is not reduced for practical urposes, ascompared with a condenser in w ich the foils are in registry, yet thegap atvthe edges of the roll is so greatly increased that the leakageand the likelihood of break-down at theseregions arel greatly reducedand the condenser may be made to serve satisfactorily and with low powerlosses, at high peak voltages.

Another feature is the electrostatic shielding of the condenser roll bythe simple ex pedient of the outermost convolution of thel outerorcathode foil completely encircling the condenser roll therewithin.

Another feature is the use of the identical metal, preferably aluminumfor the cathode,

formed and the ohmic resistance of the condenser increases, theeffective application of voltage rises in a direct proportion therewith,thereby insuring the formation of a uniform tough adherent lm on theanode foil.

Another feature is the treatment of all screws or metallic washers andsimilar parts connected to the anode and entering into the condenserconstruction, to form a di-electric film thereon, similar to that on theanode foil, thus to preclude areas of high leakage.

Another feature is thearrangement of condenser roll or rolls looselywithin an otherwise empty can, to which the cathode terminals aredirectly connected, the anode being connected to bmding posts through aninsulating can cover.

The method of impregnation and forming is not claimed herein but is thesubject matter of a divisional application Ser. No. 504,911

lfiled Dec. 16, 1930.

In the accompanying drawings in which is shown one of various possibleembodiments of the several features of the invention,

vFig. 1 is a perspective view showing the constituent elements of thecondenserCl before winding,

Fig. 2 is a perspective view showing the condenser partly wound,

Fig. 3 isa perspective view showing the condenser completely wound.

Fig. 4 is a plan view indicating themethod of forming,

' Fig. 5 is a,transverse sectional view on the line of lT ig. a, showingthe forming arrangement,

Fig. 6 is a top view of cased condenser,

7 is a transverse sectional view talren on the line .7-7 of Fig. 0,

Fig. 8 is a View in transverse cross-section of the condenser on line8-8 of Fig. 7

Fig. 9 is a fragmentary detail of vent construction, and,

Fig. 10 is a section on a larger scale on line 10-10 of Fig. 9.

Referring now to Fig. 1 of the drawings, the condenser is madepreferably of a 'pair of armature foils comprising an anode 10 and acathode 1l, of suitable film forming metal preferably aluminum, with anabsorbent separator, which may comprisean interposed sheet 12,preferably of gauze, paper or the like, of width greater than that ofthe foils, reversely folded over an end of foil 10 to provide anadditional sheet 13 superposed over foil 10. 0f course, two or moresuperposed sheets of gauze or paper may be used depending on the natureand texture of the interlay, the character of the electrolyte and thecomplete enthevoltage at which the apparatus is to be used. Theabsorbent separator should cover the total area of the anode in order toassure c. about the condenser which is .l

The cathode foil 11 is provided wlth a termi- C nal tab tpreferablyformed by slitting the foil preferably transversely near one end fornearly the entire width thereof, to provide a tongue 15, which isreverselybent as at 16,

so that the tab t may protrude beyond one.

end of the condenser roll. The anode foil 10 is similarly provided witha similar termif nal tab t2, preferably at the other end, cut from theopposite longitudinal edge to protrude'from the opposite end of thecondenser roll.

The superposed layers of foil and fabric are Wound together to provide aflattened roll with the terminal tabs t andz2 of the two foil endsprotruding from opposite ends of the roll, the anode foil tab 252 fromthe axis of the roll, the cathode foil tab t from the surface of theroll. rlhe gauze or other electrolyte retainer should extend the freeprotruding edge of t? and preferably also of the catho 'lhe outer foilpreferably aff length to provide one or two et.

Winding by. an encirclingband 28. turn or turns 1l perform the tiireeftion of a unitary capacitative chanical protector for the roil ig ndling prior to final lassembly' and asu erior conductor to dissipateheat generated in use.

The interlay of the condenser roll is now impregnated with a suitableliquid electrolyte. Thisis accomplished by immersion of the completeddry roll prepared as just set forth, in a tank containing the hotelectrolyte. The general advantages of my invention are attained by theuse of any of the electrolytes commonly employed for the purpose, forinstance glycerol and carbonate of soda, as disclosed in the priorpatent to Hiclrley No.4 900,27 8 of October '8, 1908, but the voltagewithstood by the condenser and its capacitance willdepend largely uponthe choice of electrolyte. 'f

The condenser elements are then subjected to the forming operation,preferably by laying them in trays or pans 21 of glass, aluminum orother material unaffected by the solution, filled preferably withliquid'identical with the batch in the impregnation tank. Preferably thecondenser terminals t and t2 are connected to releasable terminal clips23 and 24 respectively mounted at opposite edges of the -tray and abo-vethe level of the liquid therein. Care is taken that the foil 11 formingthe electrostatic shield is connected to the negative terminal'of thecurrent source, to constitute the cathode. In series with thecondensers, a few only of which are connected in parallel in each tray21 is connected a resistor R preferably of about 2000 ohms more or lessdepending on the voltage, the number of sections and their dimensions.Each resistor is in turn connected in series with a correspondingincandescent lamp L, the remaining terminal of which is connected to thepositive terminal of the source of current G, which is preferably of avoltage slightly in excess of the eak voltage for which the condenser isto be adapted. The trays as indicated in Fig. 4, may be convenientlyarranged in rows on racks or tables and all connected in parallel acrossthe terminals of said source of forming current G. A closed circuit jack26 is disposed in each circuit, for ready connection of a milli-ammeter,-for metering leakage current in ascertaining completion of the formlngprocess.

In the forming operation, the initial resistance of the immersedcondenser roll is very low since the current flows only across a thinfilm of conductive electrolyte of large area interposed between the twocondenser electrodes. The initial voltage across the condenser will bevery small as practically the entire volta-ge drop will be acrossresistor R and lamp L. The small voltage on the condenser roll will forma very thin film upon the anode foil 11, the electrical resistance ofwhich rises accordingly. Therefore, a larger proportion of the appliedvoltage will now be applied across the condenser foils, which bringsabout the form ation of a greater thickness of film, resulting in theapplication of still higher voltage to the condenser. In this manner thevoltage applied across the condenser foils will gradually andautomatically increase in a direct proportion with the formation of thedi-electric film, until, upon the completion of the forming operation,the resistance of the condenser will be vastly higher than that of theresistor R and practically all of the voltage will be applied across thecondenser terminals. This operaton' 1s continued until the voltageimpressed across the condenser foils is slightly in excess of the peakvoltage on which the condenser is to be used. Where the peak voltage is500, the forming voltage is preferably about 510.

With the arrangement above described,

the lamp L serves to give visual indication when -the forming lprocessis about completed. At the beginning of the forming operation, and whileit is in progress, the voltage applied to the lamp will be sufficientlyhigh for incandescence thereof, but as the formation proceeds and theresistance of the condenser dominates, thelamp will becomedimmer due to'the resulting reduction in voltage thereacross and finally willbeextinguished. The supervisor will thus be apprised of the substantialprogress of the forming operation and thereafter, with the aid of themilli-ammeter applied at the closed circuit jack 26, he will know whenthe forming operation has been completed,' at which time the condenserroll is removed from the tray. `The condenser roll thus formed, willvhave a di-electric film uoonl the anode 10 of thickness depending on thevoltage and duration of forming o eration, and the intcrlay will besoaked wit the electrolyte liquid in contactwith the film.

The individual formed condenser is preferably enclosed in a can C,preferably of the same metal as the condenser electrodes. Preferably thecathode tab t is at the bottom of the can and the anode t2 at the top,as shown in the drawings. Depending on the choice of capacitancesdesired in the' completed unit, one, two or more separate condenserrolls in parallel may be used. In the vexample shown in the drawings,three such condenser rolls D', D2 and Ds are shown,

separately and jointly encircled by a single wrapping band W ofinsulatin fiber or paper, as shown,the upper edge o which, as shown,extends above the condenser rolls. Preferably, no electrolyte, exceptwhat remains absorbed in the interlay 12-13 is put in the can, nor isthe same sealed with pitch, paraffin or other filling composition.

To complete the assembly, the one, two or more terminal tabs t of thecathode, protruding from the lower ends @f the condenser rolls areriveted, soldered or welded at 29 to a metal strip 30 extending downwardwithin the can C from near the upper end thereof, or the tabs may, ifdesired, be

-riveted or otherwise connected directly to the can. A terminal lug 3lis riveted as at 43 to the exterior of the can C, said rivets alsomechanically holding the upper end of the conductive strip 30, therebyconnecting the lower terminals of the condenser rolls to the can, whichitself serves as one terminal of the condenser assembly. The otherterminals t? of the condenser 'elements are respectively clampeddirectly as shown, under the heads of screws 33. The screws 33 extendupward Athrough the insulating cover 34 of the can and withcorresponding nuts 33', serve as binding posts. The cover is preferablymolded with shoulders 35, which lock the square headed binding postscrews, and prevent turning thereof, when the corresponding nut 33 istightened or loosened. The

can is preferably formed with a bead 36 upon which the cover 34 restsand the rim of the can is turned inward as at 37 to permanently affixsaid cover, an interposed gasket 38 assuring a tight connection.Preferably rubber washers w and wz encircle each binding post screw andare pressed against opposite faces of cover 34, thereby to prevent anylll possible ooze of electrolyte by creepage from the interlay 12--13.

The binding posts 33, rivets 29 and preferably also the rivets 43 and44, hereinafter described, are joints at which corrosive action mightoccur in the absence of other precautions. tion, these screw connectorsand rivets are made of the saine metal, aluminum, as the electrodes, andthe can, and in addition, the binding posts and other aluminum fittingsor parts, such as the washers connected to the anode, are subjected to aforming operation, prior to incorporation into the condenser. Thisforming operation is analogous to that performed on the condenser rollsthemselves. vrl'he washers and screws in a perforated can are submergedin electrolyte liquid, preferably identical with that used in thecondenser rolls, and there subiected to direct current until a thintough i'ilm has formed over the surface of elements. The anode tab t2being an integral p t the anode foil and submerged in the electrolyte issimultaneously wi i the anode.

Preferably, the condenser, after complete assembly thereof, as shown inFigs. 7 and 8, is subjected to further forming operation by connectionacross lreni-*rater toassure completion of the he condens,

described, is not subject isturbance on, as would be in curred in use ones or other rapidly moving vehicles, 3 sorbed liquid were LJ T I the conx, and ii a non-volaes erred, i ce ir esing or evaporation.

" l nce of liquid, also afantage in installa l Ji or inclined, and thusoe ntteci many relations, where may a wet condenser could not beemployed withincreasing the bulk of the apparatus.

By the present invention, the use of paper, oil cloth or other wrappingfor the individual condenser rolls, the p fallin or wax dipping and thepitch sealing, all are eliminated, with a resultant product of reducedweight, reduced cost for .labor and materials, and reduced bulk for agiven capacitance.

By the elimination of paran, waX or' pitch, there is avoided, on the onehand, any injury to the electrolytic iilm, due to the heat of' suolicomposition, when poured in, and, on the other hand, any heat generatedin use of the condenser is more readily dissipated due to the absencefrom the structure of any such poor heat conductors as paper, oil-cloth,wax or pitch. Substantial voids between the condenser roll and can aresubstantially devoid of filling composition, thereby to facilitateconvection currents of air and heat dissipation.

According to the present-inven-- No disturbing coupling eifects occur asbetween the individual condenser sections rwithin the can, each suchsection though not otherwise enclosed, being completely shieldedelectrostatically `by the outermost turn or turns of the cathode foil.

'llhe film being built up or formed upon the pre-wound condenser, it isnot subject to such injurious strain as may be incurred where the foilsection is formed rst, and the section then wound. The film by myforming method having, moreover, been built up gradually on thepre-wound condenser section, such film is homogeneous, tough andpermanent, so that the condenser remains effective even after longperiods 'of use or idleness, and requires no reforming operation to irestore it to operativeness.

rlhe formation occurring in a tray with a comparatively large quantityof electrolyte, free circulation thereof occurs and excessive heatespecially inthe inner convoutions of 'the section is avoided, and atthe same time complete retention of liquid electrolyte in theinterstices of the absorbent interlay is assured.

By the staggering of the electrode foils, there is effected amultiplication in the length of path for leakage current of dashoverbetween the sharp edge ofthe anode and'- tl e sharp of the catho-defoils, which edges the greatest electrostatic intensity occurs. Thusboth leakage current danger of breakdown are ininimivt Vf here thecathode anode foils are not breakdown the edge of the rely occur becauseof the prokiini'ty of two sharp edges of high electrostatic inten 'ty,because of the comparative imperfection oi forming at the sharp more orless jagged anode edge, and such breakdown is to be permanent.,

By staggering, the distance between the anode and cathode edges isgreatly increased, correspondingly reducing the probability of shouldsuch flash-over .nevertheless occur under an abnormal surge of voltage,it would be attenuated and therefore reforming or healing of theafiected'part on the anode edge would take place more readily.

Unlike the case of non-inductively wound wan' impregnated condensers, nomarked loss in effective area of the electrolytic condenser results bystaggering of the Jfoils, since the dielectric film will form onsubstantially the entire area of the anode, even o n that protrudingbeyond the cathode, the electrolyte in the gauze which is the truecathode being in engagement. with the entire area of the dielectricfilm.

All metal parts being of aluminum and all washers and screws associatedwith the anode being electrolytically formed, the condenser has longlife, as there are no parts, subjectl 130 to corrosion b chemical orlvanic action,

.and no objectionable variations in leakage,

tuberance within the .can formed by the in dentation, and is preferablybacked by a heavier metal washer 42, the latter assisting in securemechanical and electrical contact of the parts, held together by rivets43 and 44 through the lug 31, the can C, the strip 30 and the'backingwasher 42. J The lug, the indentation, the strip and the washer 42 areerforated at p for venting through* the ruber washer 41, which has a pinhole 41 therethrough, shown exaggerated in the drawl ings.

The pin hole 41 is normally closed and excludes dust and dirt and otherforeign matter. Under eventual gas pressure within the case, the rubberwill expand to open the pinhole and allow venting therethrough by way ofperforations p, the vent immediately closing when the pressure has thusbeen relieved. The Vent thus normally closed, also prevents escape ofany electrolyte by creepage from the moist interlay. l p

It will thus be seen that there are herein described, apparatus andmethods, in which the several features of this invention are embodied,and which in service attain the various objects of the invention and arewell suited to meet the requirements of practical use. f

As many changes could be made in the above disclosure, l'and manyapparently widely different vembodiments of this invention could be madewithout departing from the scope thereof, it i-s intended that allmatter contained in the above description or shown in the accompanyingdrawings lshall be interpreted as illustrative and not in a limiting'sense.

Having thus described my invention, whaty I claim as new and desirel tosecure by Letters Patent is 1. An elctrolytic cell'having anvactive cellelement comprising cathode and anode foils displaced with respect toeach other with substantially the entire length of the anode edgeprotruding with respect to the corresponding length of the cathode edge,said cell including a thin dielectric :[ilm closely adheringsubstantially to the entire effective area of the anode foil, means forretaining a layer of electrolyte interposed between the .cathode andanode foils and extending at least to the free protruding edge of theanode foil, a container enclosing the active cell element and presentingsubstantial voids therein, said protruding foil edge freely exposed tothe air within sai container to facilitate cooling and the escape intothe voids in the container of gas generated in the cell during o ration.

2. An electric con'denser roll inc uding convolute cathode and anodefoils having their longer edges at the ends of the roll displaced withrespect to each other longitudinally of the roll with the cathode foilprotruding at one end of the roll beyond the anode and the lattersimilarly protrudl beyond the cathode at the opposite end ldigthe roll,said condenser including a thin film of dielectric closel adherinsubstantially to the entire effective area o the anode means forretaining a layer of electrolyte interposed between the cathode andanodefoils and extending at least to the free rotrudin edge of the anode foiland means or establiiing terminal connection of the res ective foils atthe respective protruding e ges thereof.

3. An electrolytic condenser comprising elongated cathode and anodefoils of substantially equal width, an interposed sheet of librousmaterial having electrolyte absorbed therein, said foils and sheet beingconvolute to form a roll, the foils staggered with respect to each otherlengthwise of the roll with the anode edge protruding beyond the cathodeat one end of the roll and the cathode edge beyond the anode at theopposite end of the roll, said sheet of fibrousmaterial extending atleast to the protruding edges of both cathode and anodel foils.

4. An electrolytic condenser comprising a pair of metal foils ofsubstantially the same width including elongated cathode and anodefoils, the latter having a dielectric ilm over substantially the entirearea thereof, an absorbent separator sheet interposed between said filmand said cathode foil and having electrolyte absorbed therein, saidfoils and Y -each other, said separator sheet extending at least totheprotruding edges of both cathode and anode foils and terminal tabsunitary with the respective foils and extending from the respectiveprotruding edges thereof.

5. An electrolytic condenser having an active condenser elementincluding a pair of elongated metal foils withy an interposed absorbentseparator sheet, electrolyte absorbed therein, said foils and sheetbeing -rolled together, the various edges of said foils beingnon-aligned with respect to each other, said separator sheetsuperposed'over the entire area of said metal foils, a containerenclosing and determining substantial voids about said active condenserelement, said container being substantially devoid of filling composi.

tion or of electrolyte externally of the active terminal'cooperatingwith said `joint, a cover condenser element, thereby to facilitate conofinsulating material for said container, vection currents of air. and abinding post through said cover and `6.1m electrolytic condensercomprising a aflxed to the other terminal of saidconroll havingconvolute layers of anode foil and denser. y cathode foil, a dielectricfilm u on the anode 12. An electrolytic condenser comprising foil incontact therewith', the oil at the ex a sheet metal can, an electrolyticcondenser terior of the roll having an outer turn comroll thereinlongitudinally thereof, said roll pletely encircling the roll, the outerend of having one terminal near the lower end of said outer foilprotrudin beyond -the end of Said can and the other at the upper art theother foil, and direct y overlying and enthereof, a terminal lug at theexterior o? the gaging the underlying area of said outer foil. can wall,a sheety metal strip riveted to said 7. An electric condenser comprisinga roll terminal lug, the lower terminal of said conhavin convolutelayers' of anode foil end denser roll aflixed to said sheet metal stripcatho e foil, a dielectric film upon the anode an insulating cover forsaid can, a binding A foil in Contact therewith, the cathode foil posttherethrough, the outer terminal of said being at the exterior of theroll and having Condenser roll connected to said binding post, an outerturn completely encircling the roll saidcan being substantially devoidof filling the outer end of said cathode foil protrudcempollnd. ingbeyond the end of the anode and directly 13. An electrical condensercomprising an overlying` and engaging the underlying active electrolyticcondenser unit inclu ing cathode area. y cathode and anode foils, thelatter coated with 8.v An electrolytic condenser roll eempris'. adielectric film, a separator between said film ing an elongated cathodefoil, an elongated` end Seid CethOde and impregnated With anode foil,the long edges of said foils' stagelectrolyte, ametal jacket about thecondenser gered-with respect to each other and a brous unit, n canenClOSing the jaeketed unit and interla sheet impregnated withelectrolyte, having an insulating cover, the cathode havsaid foil andsheets being rolled to ether with ing; e terminal Strip electrically andmechanthe'cathode foil completely encircling the exically J'Olned t0 thebody Of the een fOr electerior of the roll the outer end of seid cathodetrical connection thereat, an electrical termifoil protrudingvbeyond theend of the anode nal cooperating with said joint, and a termianddirectly overlying and engaging the nal through the cover of the canconnected underlying cathode area. to the anode.

9. An electrolytic cell comprising mede 14. An electr1c condensercomprising a and cathode foils extending in substantially @OndeIlSeI10ll including' en anode an a superposed relationship, with the anodefoil' Cathode fOll in SllPeIpOSed relatiOnShip, a

protruding beyond the edge of the cathode thin dielectric film closelyadhering to the` foil and coated with 'e thin adhering film 0f anodefoil, a fibrous interl'ay between the di-electric, said cell having an lencircling film end the cathode and impregnated with layer of metalabout and in electrical and electrolyte, the cathode foil being at theexmechanical contact with the cathode foil and teIiOr and having One OlInOre Outer cOnvOluconstituting en electro-Statie shield, d tionscompletely encircling the roll, the outer- 10. An velectrol ticcondenser roll includ-#nest parttef the cathode foil prOtrlldng ,beingconvolute cat ode and anode foils, havyOnOl the nOde and the interlay todirectly ing their longer edges at the ends of the roll Overlieendengege the cathode area theredis laced with respect to each otherlongiunder, a metal can enclosing said roll, the tudmally of the roll,said condenser includ- CethOde being electrically cOnnected to the ing athin film of di-electric closely adhering een, and the anode beingelectrically insuto the entire effective area of the anode foil, latedWith respect to the can.

means for retaining a layer of electrolyte 15. An electrolytic condensercomprisin interposed bet-Ween the film and the cathode, a sheet metalcan, an electrolytic condenser the outer convolution of the cathode foiltherein extending longitudinally thereof completely encircling the rollthe outer end comprising an anode foil, a cathode foil, an of seidcathode foil protruding beyond the interposed fibrous layer soaked withelectroend of the anode and directly overlying and lyte,said superosed'layers in rolled relation, engaging the underlying cathode areawherewith the catho e at the exterior and presentby said outerconvolution constitutes an elecing an Outer cOnvOlntiOn encircling theroll, tro-static shield. the outermost 11. An electric condensercomprising a truding beyon the anode and the layer to conductivecontainer, a wound electrolytic dllectly OVeI'lie and engage the Cathodearea condenser roll therein and extending longithereunder, Seid IOllhnving One terminal tudinally thereof, a terminal strip protrudv teh etthe bOtiOm end the Other et the top 0f (part of the cathode foil .pro.

ing from one end of said roll and mechanithe can, meansy electricallyconnecting thel cally joined directly to the wall of said conbottomterminal with respect to the can wall, tainer, said container having anelectrical an insulating cover for the can and a binding posttherethrough and connected t'o the upper condenser terminal.

16. -An electrolytic condenser comprising a sheet metal can, alurality'of electrolytic condenser rolls therein each including aconvolute cathode, anode and fibrous nterlay, the latter having electrolte soaked therein, each of said condensers aving the cathode foil as anouter enclosing layer thereof, insulating sheet material isolating theseveral condenser rolls with respect to each other, a terminal lug onthe condenser can, the cathode terminals of the respective condenserrolls electrically connected to said terminal tab, and an insulatingcoverfor the can having binding posts therethrou h connected to therespective anode termina s of the condenser rolls.

17. An electro] ic condenser comprising an anode foil, a brous sheet anda cathode foil in superposedrelation, wound in a roll with the anodefoil protruding beyond the cathode foil at one end of the roll, thecathode foil having one or more turns at the' exterior completelyencircling said roll, the outermost part of the cathode foil protrudingbeyond the anode and the sheet to directly overlie and, engage thecathode area thereunder, a metal can enclosing said roll, the cathodeelectrically connected'to the Wall of the can and the anode electricallyinsulated from the wall of the can. 18. An electrolytic condensercomprising anode and cathode foils of aluminum, fibrous sheet meansbetween said foils and impregnated with electrolyte, a closely adheringfilm of dielectric on the anode area, a can of aluminum enclosing saidcondenser roll and presenting air spaces thereabout, an aluminum partunitary with said cathode foil and in direct mechanical contact with thelateral wall of said can for terminal connection thereto, the anodehaving a terminal insulated from the can, the voids between thecondenser roll and the can being substantially devoid of fillingcomposition thereby to facilitate convection currents of air.

19. An electrolytic condenser including an active condenser elementhaving electrodes of identical metal, a dielectric film formed on one ofsaid electrodes, an enclosing metallic can of the same metal as saidelectrodes, the wall of which determines air spaces about the activecondenser element, a terminal for said latter electrode insulated fromthe can, a terminal for'the other electrode directly afiixed to said canmechanically and electrically, metallic connecting members electricallyand mechanically associating said electrodes with their respectiveterminals, each of said mmetal as said electrodes, the voids between theactive condenser element and the can being substantially devoid offilling composition,

thereby-to'facilitate convection currents of air.

20. An electrolytic condenser including an active condenser elementhaving electrodes bers being of the same metal as said electrodes, thoseof said connecting members that are aflixed to the anode having a filmformed thereon of substantially the same composition as the (li-electricfilm on the anode foil.

21. An electrolytic condenser comprising f an aluminum can, a condenserunit containe v therein comprising electrodes of aluminum, the anodehaving an electrolytic film adhering to the active surface thereof, afibrous interlay kbetween the two electrodes impreg nated withl a liquidelectrolyte, aluminum connectors mechanically and electrically bondingthe cathode to said can, an insulating cover for said can, aluminumbinding post screws and associated metal parts of aluminum in electriccontact with the anode foil, said aluminum screws and parts having cacha film formed thereon of substantially the same composition as the anodefilm.

22. In van electrolytic condenser, a can having an indentation, a pieceof rubber in said indentation having a pin-hole therethrough, a terminallug superposed over said rubber and affixed to said condenser, said canand said lug having each al small aperture at opposite faces oftherubber piece and substantially aligned with the pin-hole therein.

23. An electrolyticl condenser including an anode foil having anintegral terminal tab, acathode foil contiguous to said anode, and anelectrolytic film upon said anode, said con-` denser section beingenclosed in a metal can, said cathode electrically connected to saidcan, an anode bindinglpost insulated with respect to said can, meansclamping said anode l terminal tab to said binding post, said anode tab,said binding post and associated metal v elements being all of the samemetal as said identical with that of said anode. 4

24. An electrolytic cell including cathode and anode foils displacedwith respect to each other with substantially the entire length of theanode edge at one end of the cell protruding beyond the correspondingedge of the cathode area, said cell includin a thin electrolytic filmclosely adhering su stantially to the' entire areaof the anode foil,means for retaining a layer "of electrolyte interposed between thecathode and anode foils and extending at least to the free protrudingedge of the anode foil, 'the cathode foil having a portion encirclingthe anode parts and 1nsulated therefrom and having an end portion no iprotruding beyond the anode and directl en- 1. ga 'ng and overlying theVcathode area t e ereun er.

25. An electrolytic condenser including convolute cathode and anodefoils having their lon er edges at the ends of the roll displaced withrespect to each other longitudinally of the roll, said condenserincluding a -thin film of dielectric'closely adhering substantially totheentire area of the' anode foil, means for retaining a layer ofelectrolyte inter osedbetween the cathode and anode foils, an extendingatleast to the free protruding edge ofthe anode foil, the cathode foilbeing at the exterior and having one or more outer convolutionscompletely encircling' the roll, f

the outermost end of the cathode foil protruding beyond the anode todirectly overlie and engage the cathode area thereunder.

26. Anelectrolytic condenser including an active condenser elementhaving cathode and anode elements of identical metal displaced withlrespect to each other with the entire length of the anode edgeprotruding beyond the cathode at one end of the condenser, said cellincluding a ,thin electrolytic -flm closely adhering substantiallyv tothe entire area of the anode foil, means for retainin a layer ofelectrolyte interposed between t e cathode and anode foils, andextending at least to the free protruding edge ofthe anode vfoil, thecathode presenting one or more convolutions at the exterior of the cellinsulated with respect to the anode and presenting a free protruding endportion in direct engagement with the underlying cathode portion, an en-DISCLAIMER 1,789,949. Alexander Georgien, Brooklyn, N. Y. ELEcTRonYTIcCELL. Patent dated January 20, 1931. Disclalmer filed February 27, 1936,bythe assignee, A670002: Corporation.

Hereby enters its disclaimer to claims 6 and 7 of said patent.` [OficialGazette March 17, 1.936.]

